荒漠结皮对土壤水分状况的影响

本研究针对鄂尔多斯沙地生物结皮进行调查 ,利用人工喷水模拟降雨分析结皮对土壤入渗性能的影响。研究表明 :生物结皮能显著地降低土壤水分的入渗速率。在去掉结皮时 ,表层下 5 cm处的土壤含水量在 1 0分钟时即开始显著增加 ,而有结皮时 ,此处的含水量则在 1 5分钟时才开始显著增加。利用圆盘入渗仪测定有结皮和无结皮条件下的土壤饱和导水率表明 :固定沙丘间地有生物结皮的土壤饱和导水率范围是 :2 9.1 0 - 82 .2 1 mm/ h;半固定沙丘有微弱结皮时饱和导水率为 1 43.5 4 - 2 30 .2 5 ;去掉结皮后土壤的饱和导水率可显著上升数倍 ,无结皮的流沙的饱和导水率最高。

The Effects of Desert Crust on the Character of Soil Water

Soil water is one of the most restrictive factors to the land productivity. This paper analysed the influence of several different desert crusts on the sandland water infiltration on Erdos Plateau. It reveals the soil crust can extremely decrease the infiltration rate. When the soil crust is taken off, the soil water content at 5cm layer beneath the surface increased markablly after 10 min by spraying the water, but with the soil crust at the same depth the soil water content began to increase after 15 min. using Simplified Disc Permeameter we determine the saturated hydraulic conductivity, the results show on the stationary sand dune with crusts the soil saturated hydraulic conductivity range is about 29.10~82.21 mm/h; one semi-stationary sand drift with thinner soil crust the soil saturated hydraulic conductivity range is about 143.54~-230.25 mm/h; when taken away the soil crust, the soil saturated hydraulic conductivity is several times higher, and the active sand drift without any crust has the highest saturated hydraulic conductivity.